Numerous techniques and protocols are utilized to enable computing devices to connect to and communicate over packet-switching, wide area networks (WANs). For example, Internet Protocol version 4 (IPv4) and Internet Protocol version 6 (IPv6) may be used to enable devices to exchange packet data over the Internet. For the IPv6 protocol, devices may connect to a WAN using 128-bit addresses that include unique prefixes that are typically 64-bit in length and that are administered by a network entity. In common scenarios, a router device (e.g., a Wi-Fi router, a software-enabled access point (“softAP”) device, etc.) receiving such a prefix via its modem may share the same prefix with all client devices connected to a local area network (LAN) established by the router device such that all traffic to the WAN from the router device includes the same prefix. For example, LAN client devices connected to the router device may combine the shared prefix with a unique identifier (e.g., a MAC address, etc.) in order to generate their IPv6 address for packet transmissions. Such uniformity of prefix may be problematic for network carriers and other entities that desire to accurately identify different devices using the WAN and to bill based on usage. Further, although some duplicate address detection processes may be executed when LAN client devices generate their IPv6 address using a shared prefix, other LAN client devices may have the same address, causing redundancies in IPv6 addresses.
Some router devices (or packet data network (PDN) connections) may be configured to utilize a “prefix delegation” feature, such as described by the 3rd Generation Partnership Project (3GPP) (e.g., within the standards document 3GPP TS 23.060 V10.4.0). Implementing such a feature, a router device may obtain (via its modem) a single network prefix that is shorter than the default prefix size (e.g., 64-bit or /64). For example, the router device may obtain a short prefix 56-bit in size (or /56). The router device may allocate unique prefixes (e.g., 64-bit in length) used for IPv6 stateless auto-configuration using the bits that are not used in the short prefix (e.g., 56-bit in length, etc.), allowing a certain number of LAN client devices to all have unique prefixes. For example, when the default prefix is 64-bit long and the prefix delegation router device obtains a short prefix that is 56-bit long, the router device may utilize 8-bits to generate a fixed number of 64-bit unique prefixes based on the short prefix. Each of the generated 64-bit unique prefixes may then be assigned to different client devices connected to the router device (e.g., via a LAN connection). The router device may generate and assign 64-bit length unique prefixes upon request from connected LAN client devices. In this way, the remaining address space from the short prefix can be delegated to the router device (or PDN connection) using prefix delegation, so that the router device may provide on request a certain number of LAN client devices unique IPv6 addresses that fit into the total available IPv6 address space.
Prefix delegation is often utilized by some router devices. For example, a main use of prefix delegation is typically for a service provider to assign a prefix to a customer-provided equipment (CPE) device acting as a router between a subscriber's internal network and the service provider's core network. This may be useful for companies that need a large address space.
Router devices may not continually have an IPv6 data connection (i.e., a data call, a backhaul connection, a WWAN connection, a Wi-Fi connection, a USB connection, etc., to an access point or base station which provides connections to carrier networks and/or the Internet) established upon boot up. Some router devices, such as 4G and/or 3G based mobile routers (e.g., a Wi-Fi routers establishing 4G and/or 3G wireless connections to the PDN, softAP devices establishing 4G and/or 3G wireless connections to the PDN, etc.), may bring up a data connection on an as needed basis. For example, the router devices may establish LAN connections to the various LAN client devices upon boot up, but may only establish a data connection as requested, such as by a user selection enabling a data connection, an application requesting the establishment of a data connection, etc. Additionally, the data connection can be terminated and re-established due to factors inherent in wireless connections, including connection interruptions caused by the router device moving (e.g., being used in a car, on a train, while a user is walking, etc.), wireless interference, etc.
When a router device does not support prefix delegation, the lack of a continuous data connection may not present a problem because each time a data connection is established the router device will send unsolicited router advertisements to the pre-defined multicast “all nodes address.” The use of the “all nodes address” will cause the router advertisement to be received by all connected LAN clients. In this manner the LAN clients will get a global IPv6 address each time the data connection is established/re-established.
When prefix delegation is utilized by a router device, each time a data connection is brought up (i.e., established or re-established), the network provides a delegated prefix, and all LAN clients (e.g., WLAN clients, USB tethered clients, etc.) connected to the router device will receive a unique prefix based on the delegated prefix. When using prefix delegation, each client is required to use the stateless address configuration procedure in order to receive its assigned unique prefix (i.e., each client must send the router device a solicitation message).
However, the need to have each client request its unique prefix with a solicitation message when using prefix delegation may pose a problem as LAN clients already connected to the router device when then data connection is brought up, may not send out solicitation messages. For example, the LAN client's stateless address configuration may have timed out and the LAN client may not send further router solicitation messages as described in Network Working Group Request for Comments 4861, section 6.3.7 “Sending Router Solicitations” available at http://www/rfc-base.org/txt/rfc-4861.txt. Because the already connected LAN clients may not send router solicitation messages, the connected LAN clients may not request and receive their unique prefixes. Without their unique prefixes, even though the data connection may be up (i.e., established or re-established), the already connected LAN clients may not access the Internet over IPv6 as the already connected LAN clients will not have a valid unique prefix.